Aluminium powder is used as a solid fuel for rocket engines

Consider the following statements :

1. Aluminium powder is used as a solid fuel for rocket engines.
2. Compared to liquid fuel propelled rocket engines, the thrust per amount of fuel burned is higher in solid fuel propelled rocket engines.

Which of the statements given above is/are correct?

1.  1 only
2.  2 only
3.  Both 1 and 2
4.  Neither 1 nor 2